72 
Psyche 
[June-Sept. 
two pairs of sclerotized subapical (lateral) plates in both 
sexes. In the males of equina and longipennis, the anterior 
pair is small and fused with the median tergal plate, yet 
recognized by the very long setae it bears. In addition, 
these two species have in both sexes three median tergal 
sclerotized plates, which are much smaller in the female 
than in the male. Median tergal plates are lacking in both 
sexes of variegata, ruftpes, struthionis , and hirsuta, and in 
the female of camelina. The male of camelina, however, has 
an extensive anterior sclerotized median plate, immediately 
behind the basal tergal sclerite of the abdomen, and poste- 
riorly a pair of small, median tergal plates. In the female 
of longipennis and equina the anterior pair of subapical 
(lateral) plates is slightly smaller than the posterior pair; 
it is larger than the posterior pair in the female of variegata , 
hirsuta , camelina and struthionis; and both pairs are about 
the same size in the female of rufipes. In the males of 
variegata, rufipes, hirsuta, camelina and struthionis, the 
anterior pair of subapical plates is very large, the posterior 
pair very small and readily overlooked. I have not exam- 
ined the structure of the abdomen of fulva and martinaglia. 
In the male genitalia, the claspers (or parameres) are very 
similar in equina, longipennis, fulva, variegata, rufipes and 
struthionis, being more or less slender, straight and rod-like, 
ending in a point. In camelina they are of much the same 
rod-like type, but thicker, curved in profile and ending in a 
blunt, somewhat knobbed point. They are quite aberrant 
in hirsuta, being thick and beam-like, with a broadly trun- 
cate and slightly emarginate tip. The genitalia of martin- 
aglia are unknown. 
To sum up, the nine species of Hippobosca now recognized 
may be divided into four groups, expressing relationship 
based on structural characters: (1) equina, longipennis and 
fulva; (2) variegata, rufipes, hirsuta and possibly martin- 
aglia; (3) struthionis; (4) camelina. 
The following key supersedes that of my earlier paper 
(pp. 308-309) . H. martinaglia is inserted from the descrip- 
tion only. 
1. Second longitudinal vein (R2 + 3) long, about as long 
as or longer than last section of third longitudinal, 
reaching costa much beyond tip of first longitudinal 
